Comparison of postocclusion surge between venturi and peristaltic phacoemulsification pump type.

PURPOSE: To evaluate the postocclusion surge characteristics of venturi and peristaltic-generated vacuum levels.

SETTING

University setting, Salt Lake City, Utah.

DESIGN

Experimental study.

METHODS

The Johnson & Johnson Veritas machine and Ellips FX handpiece with standard pack tips, with variable peristaltic and venturi settings, were used. A standard quadrant removal preset had the settings: vacuum 450 mm Hg, aspiration 60 mm Hg, and bottle heights 41 cm and 81 cm. To monitor pressure changes, a rubber disk was fixed within a sealed chamber fitted with an electric sensor. The phacoemulsification tip was inserted through a small opening; the foot pedal was set to position 3. The tip was in contact with the disk to replicate tip occlusion and then pulled from the disk to simulate occlusion break. 10 trials were performed for each intraocular pressure and vacuum type.

RESULTS

A significant difference ( P < .01) was observed in postocclusion surge magnitude between venturi and peristaltic pumps at 41 cm and 81 cm bottle heights. No significant difference was observed in surge duration at either bottle height. Average duration of surge for venturi and peristaltic at 41 cm was 1.56 ± 0.75 seconds and 2.25 ± 0.40 seconds, respectively; at 81 cm 2.27 ± 1.41 seconds and 2.90 ± 1.10 seconds, respectively.

CONCLUSIONS

Data suggest that at bottle heights of 41 cm and 81 cm, with indicated settings, venturi settings on the Veritas platform have a lower postocclusion surge magnitude compared with peristaltic settings. This indicates that there may be a platform-specific lower risk for posterior capsular tear when using venturi settings in the Veritas system during cataract surgery.